I origionally posted asking about differences of mid pipes. Got many different responses good/bad about upgrading it. Now my question is how many of you have upgraded your mid pipe with no problems, like many of you and my tech has said they cause boost creep and cause motors to POP! Is there a good way to prevent boost creep? Maybe put a high flow cat on? Thank you!

 

I am not 100% on this, but I believe that tuning is your solution and having the proper equipment to tune.

with a midpipe (assuming that is coupled with a downpipe and a catback) you will need an ECU of some sort to control the fuel curves. The stock ECU can only handle so much flow (even at 10psi) that it will run lean.

Boost control is also important. from what I have seen, people are having alot of good luck with dual manual boost controllers. This will enable you to tune the precontrol and the secondary (my terms are probably wrong, but two are neccessary to have full tuning control) Some have had goo luck with a single boost controller however i think it created more difficulties balancing hte boost and such.

Tuning for the right A/F ratio is KEY. it's not the horsepower that will pop your engine. It is detonation. If you run lean (not enough fuel) then you will get detonation. this is what wrecks havoc on apex seals and such. Too much fuel is safer than not enough. Proper tuning is worth its weight in gold, especially if you want to step up to more boost. The stock ECU is pretty much limited to 10psi, from what I have read.

Hope this helps.

Oh... and search :P (had to get that in there)

 

well everycar is different and it depends on your mods as well. but a high flow cat is the way to go for no boost creep. if you want the extra power of a midpipe you have to invest more money to make the car safe. either by porting your wastegate(which is the better way) or by restricting exhaust flow.

 

Ah yes, forgot to mention wastegate porting. helps with boost creep.

I have heard nothing but good results from high flow cats. better noise quality I am sure too.

 

I put on my Rx7store midpipe without a tune...Its been almost a month now and my car is running as good as new...

I was told DONT put on the midpipe without a tune, etc, etc,....But I have yet to see any problem with it...I also hava a TurboXs BOV though...So I am sure thats helping with the boost creep...

Dont let people blow smoke up your *** on these forums....You have to filter out some of the bullshit every once in a while...

If you want me details on my setup or have questions just pm me...

Thanks
Shawn

 

Thank you for the great replies. my current setup is as follows:

-Brand new (not rebuilt) transmission from Mazda, added B&M shortshifter with MOMO ****.
-Brand new 99 Spec Turbos from Rotary Performance
-ECU upgraded with fully programmable Apex'i PFC
-Suspension - Koni Yellow adjustable shocks, w/ Eibach springs, and RE rear toe-links
-Exhaust - M2 Downpipe and Racing Beat Single Tip Cat-Back exhaust.
-Intake - HKS Racing Suction
-Cooling - Koyo Aluminum Radiator w/ aluminum AST new coolant lines.
-Intercooler - Greddy 2 Row Front Mount w/ Greddy Elbow and J-Spec Y pipe
-Greddy Spec II Boost Controller.
-Greddy pulley kit.

if this helps any with your answers
thanks again

 

AWD-RWD - If you do have boost creep problems, they are easily solved with restrictor plates. A lot easier and cheaper then wastegate porting, a lot more reliable and lighter than cats. Do a search for restrictor plates.

- JyRO

 

With the Greddy Spec II Boost Controller you shouldn't have any problems.

 

AWD-RDW racer:
Listen to your mechanic and do a search here. If you increase the flow capabilities of the engine beyond the ECU's ability to compensate with more fuel, you will detonate. ALOT of restriction to the engines ability to move air is removed with a midpipe and you overwhelm your WG. You have a PFC, which is good so you can add fuel to an extent, but it still will not cure boost creep. Not sure about the restrictor plates mentioned, but AFAIK from everything I've read here, only porting the WG, or adding some restriction back into the equation (ala: Hi-flow cat)... will cure creep. A boost controller will cure boost SPIKE, but WILL NOT HELP boost CREEP.
To Chunky, not trying to pick a fight, but I think it's you who are blowing smoke up his ***. You've likely only had your car for a few months, and your midpipe even less. Still your insisting that it's OK despite the collective knowledge and experience from virtually everyone else here on the forum. Go ahead and go WOT one cool morning or evening and let us know how it goes. It's an attitude like that, that leads to alot of "PARTS FOR SALE" ads.

 

lol thanks. good info to consider, still dont see how putting a catless pipe but adding a restrictor plate will increase flow (though it may decrease creep)
cant you only flow as much exhaust as your smallest pipe opening? by all means correct me if I am wrong. Im just trying to find a solution that will "safely" increase power.

 

You WILL get boost creep. You can not tune well for boost creep power fc or not. Restrictor plates, porting your wastegate, or a high flow cat will reduce boost creep. I experienced no problems with my midpipe(until I popped my motor one night).

 

Including your post. You are wrong. Bad advice. End of story.

You are wrong. Bad advice. End of story.


95% of people who install a full exhaust (midpipe) experience boost creep. That's based on several years worth of hundreds of owners' experiences. Not the BS spouted by a single owner who's been running a midpipe for a month.

The solution is to:

*install restrictor plates
*port the wastegate
*don't run a midpipe and go with a hi-flow cat instead

 

I had boost creep when i first got the car. I had to port the WG aand machined my own restrictor plate. Now im just really getting tired of how loud the midpipe makes the exhaust so much louder but it does sound great at WOT. So im buying a universal cat to weld into the mid pipe.

 

A BOV can in no way help with boost creep, in fact a BOV upgrade has 0 performance value unless you run high boost and the stock BOV starts leaking.

Running a midpipe increases air flow which means you need more fuel, even if you manage to keep boost to 10psi. That is why you would need a restrictor plate to limit the air flow (therefore fuel) back down to closer to stock levels. Basically, now you have a car with the same performance as before but it smells worse and makes more noise.

Because the FD has a MAP sensor it does not measure air flow, and the fuel needs to be added by modifying the maps. In short, you need to be ready with $1000 worth of ECU and $500 in tuning before you can spend the $250 on a mid pipe unless you want to spend $2500+ on a new motor in the next couple months.

 

i have about .5 psi of creep w/my straight exhaust and no porting or plates. IMO, it doesnt make sense to slap a midpipe in and then throw plates on to restrict the flow again.

I will say I like knowing I can shoot flames for some reason lol.

 

I hardly flame people for misinformation, but this one deserves a flame. Also, do note that others have covered this.

Ahem.

This is the largest crock of **** I have heard in on this board in a long time. What causes boost creep, you say? Well, boost creep is caused by an excess in exhaust flow which exceeds the capacity of the wastegate. In turn, you have excess boost pressure which is not compensated for by our ECUs.

Now, how would a BOV prevent this from happening? A BOV simply purges boost pressure when it senses a set amount of vaccum due to the throttle plates closing to prevent the turbo from surging. When there is boost, the BOV is CLOSED. IT HAS NOTHING TO DO WITH BOOST CREEP WHICH IS ONLY SEEN WHEN THE THROTTLE IS OPEN.

It is true that some people have been able to run midpipes without seeing boost creep. Using this as a blanket statement is like saying "heroin is a-okay since I know a guy who was on it for years and didn't die". Such findings can be due to variables such as high exhaust restrictions, turbo manifold leaks, etc. I have even heard of people who see slight boost creep with high flow metalicats. It all varies from setup to setup, but a large majority of the stock sequentials w/ full exhaust usually see boost creep.

Maybe it's you that we should be filtering.

 

ahh this is all good to know because i was debateing on waiting till i get a pfc or get it on now and see what happens... this is good.. now i gotta start saving up lol.. i am getting an IC first then pfc then suspension since mine sucks

sorrry to ask on here but what IC would be best fit and all in the car

 

I am not saying running a midpipe without proper modifications WONT blow your motor....I am saying I am running a midpipe WITHOUT proper modifications and my car is running fine...

I simply gave my personal expierences with the whole upgradeing the midpipe situation...I, in no way, said it is "OK" to run a midpipe without proper modifications...

I just so happen to be one of those people that is running the midpipe without any problems at the moment...

Now sure in the long run, my motor will MOST LIKELY go POP and take a fat **** on me...I am not doubting that factor...

But for now I am NOT in the "Large Majority Group"

Thanks guys,
Shawn

 

yeap listen to rynberg here, install a hi-flow cat, you can buy a good one for 300-400

 

I agree with the filtering bullshit part.

 

This is the second topic about the same subject getting the same responses. Look AWD, you can search the forums for midpipe only in this section and you'll get atleast 100 threads to READ. So do so.

Also, you're getting the exact same responses as before. DON'T put a mid pipe on. You already said you were boosting at 14psi, creep will surely pop your motor. Get a high flow cat you'll be more happy for now.

 

I was running a mid pipe on my new FD. No boost creep, BECAUSE, the previous owner never replaced the stock cat back. He was an idiot. Dave at KDR rotary told him to get rid of the midpipe because that is what blew his engine. But, he refused. Thank god I got the car before he did any damage. The stupid part is why put a midpipe in and not replace the cat back? Luckily I believe that is what has saved the engine.
Anyway, I just replace the mid pipe with a Bonez cat. I just don't feel like rolling the dice with a brand new engine.

 

I ran a MP with no boost creep for about a year. And then one day I started experiencing boost creep; I have no idea why it started since I didn't change anything on the car. Who knows, but now I have to keep a close eye on the boost gauge to keep things under 13psi (I run an rx7.com chipped ECU).

So looks like I will be taking the turbos off soon to port the wastegate. fun

 

I seem to have no issues but I run a 3" mid and down pipe into the factory cat back. Boost is 12-10-12 and it is quiet. Everything else is stock. When I change the cat-back Iwill need to follow the advice you guys are giving.
I believe fuel quality is a major issue too. I would run race gas if it wasn't so expensive to keep detonation at bay.

 

With my first FD when I installed the midpipe I had boost creep. I used Supertrapp plates to fine tune the exact amount of minimum back pressure needed to prevent creep.

With my second, present, FD, I also had a wide open exhaust but, I installed a metallic substrate cat converter. These cats flow considerably better than the ceramic high flows, thus, I ended up with boost creep again.

So, back to the use of Supertrapps. Supertrapp factory claims that using 24 plates give full unristricted flow, equaling a straight pipe flows. So, I had no boost creep at a starting value of 15 plates, kept building it all the way to 24 and still no boost creep. So, now I removed the back, blocking plate from the Supertrapp, creating a full flow straight exit but, still having the 24 plates installed at the end of the exit pipe. Interestingly no boost creep.

Apparently the amount of additional back pressure that I needed with the met. cat was so tiny that it was satisfied with the minor turbulance that the Supertrapp plates provided even in the totally open exit configuration. An additional benefit is that they still provide noticably reduced sound levels as apparently those plates still allow for the soundwaves to be altered.

Albert